Definition
New_Quad.jpg
This unique figure is a quadrilateral with a single angle measuring greater than 180
This quadrilateral is unique for the following reasons:
- It is a concave figure with an angle measuring greater than 180
- The diagonals form outside the figure
- Only two triangles can be formed inside the figure






Properties

Side Properties
1. 2 consecutive pairs of sides are congruent
*The consecutive side pairs refer to the top side pairs and bottom pairs in this orientation of the New Quadrilateral

New_Quad_20.jpg





Angle Properties
1. The base angles are congruent
*The base angles refer to the measured angles below (Angle DAB & Angle DCB)


New_Quad_25.jpg



2. Sum of the base angles is congruent to the measure of the top angle

*Top angle in this orientation of New Quadrilateral
New_Quad_22.jpg
Angle DAB + Angle DCB = Angle ADC
36.66 + 36.66 = 73.32
36.66(2) = 73.32






Triangle Properties

1. Opposite triangles are congruent
New_Quad_23.jpg
Example Proof
Prove: Triangle ADB is congruent to Triangle CDB

New_Quad_30.jpg